Electric switch



June 14, 1932. F. F. BRANDCET AL ELECTRIC SWITCH Filed Oct. 8, 1931 Figl.

Inventors. Frederick F. Brand, Josepl: X.Mathieu,

The i r Attor-n ey Patented June 14, 1932 UNITED STATES PATENT OFFICE FREDERICK 1. BRAND AND JOSEPH X. MATHIEU, OF PITTSFIELD, MASSACHUSETTS, ASSIGNORS ,TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ELECTRIC SWITCH Application filed October 8,. 1931. Serial No. 567,690.

Our invention relates to electric switches. Transformers are often provided in which one of the windings is formed with two parallel sections, each section having taps connected to a switch for changing the tap connections. With this arrangement, the tap connections may be changed without interrupting the current in the tapped winding, each of the sections of this winding being arranged to carry the entire current While the tap connections from the other section are being changed. The general object of the present invention is to provide an improved switch which may be used for this purpose F and which shall be simple in construction and reliable in operation.

The invention will be better understood from the following description taken in connection with the accompanying drawing in which Fig. 1 is a face view of a switch constructed in accordance with the invention, part of the structure being broken away .to reveal details; Fig. 2 is a sectional View on the line 2-2 of Fig. 1; 3 is a sectional view on the line 33 of Fig. 1; and Fig. h s a diagrammatic view of one arrangement of transformer winding connections including a switch constructed in accordance with the invention.

Like reference characters indicate similar parts in the different figures of the drawing.

The switch shown in the drawing includes two spaced parallel plates 10 and 11 formed of insulating material. These plates 10 and 11 are held in spaced relation by a central shaft 12 and a plurality of conductive bars 13 equally spaced from each other and equally spaced from the shaft 12. Each of the bars 13 is'secured at one end to the plate 11 by a bolt 14 and at the other end by a terminal 15. A conductive strip 16 is riveted to the inner face of each of the bars 13 and the two ends of each of these strips 16 are turned inwardly at right angles to the shaft 12 to form the stationary switch contacts.

The shaft 12 is surrounded by two insulating bushings 17 and 18 on which are mounted two spaced parallel Geneva .gear wheels 19 50 and 20 respectively. The two Geneva gear wheels 19 and 20 are driven by two, driving members.22 and 21 respectively secured to a shaft 23 mounted in bearings in the plates 10 and 11 and provided with a hand wheel'24 for operating it. Each of the driving members 21 and 22 includes a pin 25 arranged to engage its gear wheel and rotate it one step for each complete revolution of the driving member. The two pins 25 are displaced 180 from each other so that the two Geneva gear wheels are rotated step by step and alternately as the shaft 23 is turned.

Two conductive annular plates 26 and 27 are bolted to the two gear wheels 19 and 20 respectively but with spacers 28 to keep the outer parts of the plates away from the toothed edges of the gear wheels. The plates 26 and 27 are parallel to each other and surround the shaft 12 from which they are insulated by the bushings 17 and 18. The spacing of the plates 26 and 27 is substantially equal to that of the inwardly turned ends of the contact strips 16. The plates 26 and 27 have edge projections 29 and 30 which carry movable contacts 31 and 32 respectively. Each of the movable contacts 31 and 32 includes two sections which are pressed yieldably toward each other by a spring on a through bolt as indicated in Fig. 2. The inner end of each of these contact sections is connected conductively to its supporting plate 26 and 27 by a flexible conductor 47. The outer ends of the contact sections'extend beyond the ends of the projections 29 and 30.

The inwardly turned contact ends of each of the contact strips 16 he in the paths of the outer ends of the movable contacts 31 and 32 respectively. The contact strips 16 or at least their inwardly turned ends have beveled or sharpened edges so that they will separate the two sections of the movable contacts 31 and32 as the movable contacts are moved from one contact making position to the next. The angular spacing of the contact strips 16 is, of course, equal to the angular movement of each of the movable contacts 31 and 32 during each step of its intermittent motion. Thus, the two conductive annular plates 26 and 27 may be conductively connected to any desired one of the fixed contact strips 16 and may be moved alternately along the contact ends of these strips.

Two fixed contacts 33 and 34 are carried by conductive members 35 and 36 which are secured to supports 37 and 38 mounted on the plates 11 and 10 respectively. Each of the fixed contacts 33 and 34 includes two sections pressed yieldably toward each other by a spring and are otherwise similar to the two movable contacts 31 and 32 so that they need not be further described. The edges of the annular plates 26 and 27' extend between the sections of the two fixed contacts 33 and 34 respectively so that the plate 26 with its movable contact 31 is always connected to the member 35 which forms a terminal of the switch and the plate 27 with its movable contact 32 is always connected to the member 36 which forms another terminal of the switch.

The operation of the switch will be clear from the diagrammatic view in Fig. 4 of the drawing where the two end contacts of each of the strips 16 are shown connected to one of the taps 37, 38, 39 and 40 of a transformer winding 41. In the positions shown in Fig. 4, the two movable contacts are both connected to the contact strip 16 which is connected to the tap 37. The fixed contacts 35 and 36 are connected through circuit breakers 42 and 43 respectively to the ends of a reactive coil 44. The center of the reactive coil 44 and the end of the winding 41 opposite its taps are connected to the two conductors 45 and 46 of an electrical circuit. The current between the conductors 45 and 46 flows in two parallel paths between the center of the reactive coil 44 and the winding tap 37, one of the paths including one half of the coil 44, the circuit breaker 42, and the annular plate 26 with its fixed contact 33 and its movable contact 31, and the other path including the other half of the coil 44, the circuit breaker 43, and the annular plate 27 with its fixed contact 34 and its movable contact 32.

The function of the switch in the arrangement shown in Fig. 4 is to change the voltage ratio of the transformer without any interruption in its operation. If the hand wheel 24 with its shaft 23 is turned one revolution in a counter clockwise direction, the movable contact 31 will first be transferred to make connection with the tap 38, the entire current being carried through the movable contact 32 while the contact 31 is between its two contact making positions. The circuit breaker 42 may be opened while the contact 31 is being transferred in order to prevent excessive sparking or arcing at the contacts. The reactive coil 44 will prevent excessive circulating current between the two taps 37 and 38. The movable contact 32 is then similarly transferred to make connection with the tap 38, the circuit breaker 43 being opened during the transfer. The switch connections may thus be transferred in either direction to any desired tap of the transformer winding 41.

The invention has been explained by describing and illustrating a particular construction and application of switch but it will be apparent that changes may be made without departing from the spirit of the invention and the scope of the appended claims.

lVhat we claim as new and desire to secure by Letters Patent of the United States, is:

1. A switch including a shaft, two parallel spaced conductive plates supported on said shaft, means for rotating said plates alternately about said shaft, a movable contact secured to each plate, fixed contacts supported in the paths of said movable contacts, and a fixed contact supported in contact with each of said plates.

2. A switch including a shaft, two parallel Geneva gear wheels mounted on said shaft, means for rotating said gear wheels alternately about said shaft, two spaced conductive plates secured to said gear Wheels and insulated from each other, a movable contact securedto each conductive plate, fixed contacts supported in the paths of said movable contacts, and a. fixed contact supported in contact with each of said plates.

3. A switch including a shaft, two parallel Geneva gear wheels mounted on said shaft, means for rotating said gear wheels alternately about said shaft, two annular spaced conductive plates secured to said gear wheels and insulated from each other, each annular plate having an edge projection, a movable contact secured to each of said projections, fixed contacts supported in the paths of said movable contacts, and a fixed contact supported in contact with each of said plates.

4. A switch including two parallel shafts, two parallel Geneva gear wheels mounted on one of said shafts, two driving members secured to the other shaft and arranged to rotate said gear wheels alternately, two annular conductive plates secured to said gear wheels and insulated from each other, a movable contact secured to each plate, fixed contacts supported in the paths of said movable contacts, and a fixed cont-act supported in contact with each of said plates.

In witness whereof, we have hereunto set our hands.

FREDERICK F. BRAND. JOSEPH X. MATHIEU. 

